Since Mazda's customer support for the USB port is total crap, here's some (hopefully) helpful information about what works for me in the USB port (music files), and what doesn't.

1. my iPhone 13 Pro is cabled in to one of the ports all the time (it works via CarPlay on both just fine.)
2. What DOES work (right out of the packaging):
   1. 512GB PNY USB 3.2 Flash Drive I bought at Staples
   2. 1TB Sandisk Ultra Dual Drive deluxe (from Amazon)
3. What DOESN'T work:
   1. my 160GB iPod Classic
   2. Sandisk 1TB USB Extreme SSD
   3. Seagate One Touch 2TB External Hard Drive Slim Portable HDD USB 3.0 / USB 2.0

I'm able to play FLAC, ALAC, and MP3 files flawlessly.

My wife has a 2023 Miata GT, and my iPod Classic DOES work in that. I never tested the SSDs in the Miata, so I can't attest to those, but I'm 99% certain the flash drives will work.

 

BTW, the Bose system really a) sings when you feed high quality audio into it, and b) drives home how ****ty satellite radio sounds in comparison.